Software Engineer II - Inline Mailflow

About the Role Abnormal AI is looking for a Software Engineer to join the newly formed Inline Mailflow team. This team is building Abnormal’s next-generation SMTP relay infrastructure - a scalable mail flow harness that will power our outbound email security motion and long-term SEG displacement strategy against competitors. The Inline Mailflow team will operate as a close counterpart to the current Inline Remediation team and will live within the Message Platform group. The relay harness will serve as the foundation for a growing portfolio of capabilities including outbound filtering, DLP enforcement, misdirected email detection, IP management, encryption, archiving, and DMARC enforcement. The ideal candidate has strong backend and distributed systems experience, a deep appreciation for email infrastructure, and the ability to thrive in a fast-moving 0-to-1 build environment. What you will do Design and implement core components of the SMTP relay harness, including Mail Transfer Agent (MTA) infrastructure, scalability, IP management, encryption, and DMARC support, working from conception through production operation. Co-build the production relay alongside existing infra engineers, ramping toward full ownership of defined services as the product matures through Q3 and into EA. Collaborate with PMs and Solutions Architects to translate customer requirements into reliable, opinionated relay configurations that support inbound and outbound use cases. Own and operate tier-0 mail flow services that handle high volumes of enterprise email at production SLA, participating in on-call rotations and driving continuous reliability improvements. Contribute to technical design discussions on how the relay integrates with existing inline products (outbound DLP, behavioral outbound, misdirected email), helping define the architecture of the broader Mail Flow platform. Raise the bar of engineering excellence by contributing to knowledge sharing, runbooks, and professional development within the team. Must Haves BS degree in Computer Science, Applied Sciences, Information Systems, or a related engineering field. 3+ years of backend software development experience with distributed systems, designing and building production services. Hands-on experience with our stack: Go and/or Python. Experience building features and components from scratch and owning them in production, balancing feature development with operational work. Comfortable with ambiguity and 0-to-1 projects where you help shape requirements alongside product and engineering stakeholders. Experience working with distributed teams; proficient in asynchronous and written communication. Nice to Have Solid understanding of email protocols and infrastructure (SMTP, MTA architecture, DNS, SPF/DKIM/DMARC). Experience with our extended stack: AWS, Kubernetes, Django, Spark, Prometheus. Familiarity with email security products or Secure Email Gateways (SEGs) such as Proofpoint, Mimecast, or Microsoft Defender. Experience with email deliverability concepts: IP reputation, bulk sending infrastructure, bounce handling, or feedback loops. Familiarity with containerization using Docker or similar technologies. #LI-PP1 Abnormal AI is an equal opportunity employer. Qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, disability, protected veteran status or other characteristics protected by law. For our EEO policy statement please click here. If you would like more information on your EEO rights under the law, please click here.